不同高岭土系黏土性质及在催化裂化催化剂中的应用

随着原料油重质化、劣质化程度逐渐增高,催化裂化催化剂基质不仅需要保证催化剂有良好的磨损性能和流化性能,还需要具有适当的孔和一定的酸性对原料油中的大分子进行预裂化。半合成催化裂化催化剂中的高岭土系黏土对催化剂性能有重要影响。高岭土可直接或经酸、碱改性作为催化剂基质,也可通过原位晶化技术合成分子筛或含有Y型分子筛的催化剂。累托石通过交联反应可以合成层柱分子筛用于催化裂化催化剂制备。埃洛石因其管状结构,作为基质时催化剂具有孔体积和比表面积大及活性高的特点。对催化裂化催化剂中高岭土系黏土结构、改性方法及在催化裂化催化剂中应用进行综述,并对今后高岭土在催化裂化催化剂中的研究方向进行展望。     

催化裂化催化剂专用高岭土改性研究进展

介绍了高岭土的组成、特性及应用,综述了催化裂化催化剂专用高岭土改性方法及其研究进展,并对今后的高岭土改性研究提出了建议。     

催化裂化催化剂的研究与应用

催化裂化工艺技术已经成为原油二次加工的重要手段,而催化裂化催化剂又是该工艺的核心。本文着重探讨了催化裂化催化剂的研发情况,主要包括改性高岭土、中大孔硅铝以及新型催化裂化催化剂基质材料的研究情况,以及催化裂化催化剂活性组分的研究情况。最后介绍了各种催化裂化催化剂的应用情况,指出了将来催化裂化催化剂的研究斱向。     

催化裂化干气乙烯低聚催化剂改性研究

乙烯低聚制低碳烃是利用催化干气乙烯资源的有效途径。本文在固定床反应装置上,对催化裂化干气乙烯低聚催化剂进行了改性研究。结果表明,高岭土是合适的催化剂载体,磷改性可以降低水热处理过程中的酸量损失,含磷老化剂能够在乙烯转化率损失不多的前提下获得最高的烯烃收率。     

高硅铝比小晶粒NaY分子筛/高岭土复合物的合成及其催化裂化性能

以两种不同粒径的高岭土为原料,采用水热法合成了高硅铝比小晶粒NaY分子筛/高岭土复合物,通过XRD、SEM、晶粒度分析和N₂物理吸附等表征手段对复合物进行了结构和形貌表征。结果表明,与商品NaY相比,高岭土合成样品的结构稳定性和水热稳定性显著提高,以细化高岭土为原料合成样品的晶粒尺寸达310 nm,比表面积达807 m²·g^-1。以改性NaY分子筛/高岭土复合物为活性组分制备了催化裂化催化剂,采用NH₃程序升温脱附(NH₃-TPD)技术对其酸性特征进行了分析,并在小型微反装置上对其重油催化裂化性能进行了评价。研究结果发现,随着骨架硅铝比增大,催化剂表面酸中心强度增加,而酸量下降。采用细化高岭土合成的NaY分子筛/高岭土复合物的分子筛晶粒更小,催化剂酸中心数量以及催化裂化性能均大幅度提升。随着高温焙烧高岭土/偏高岭土质量比的增加,合成产物中的高岭土基质含量增加,催化剂表面酸中心强度下降。以原料高温焙烧高岭土/偏高岭土质量比为0.5,骨架硅铝比为6.1(摩尔比)的样品制备的催化剂,去柴重油转化率高达85.4%,同时有高达64.2%的汽油收率,表现出优异的重油催化裂化性能。     

磷改性高岭土型流化催化裂化催化剂的表面酸性及裂化性能的研究

采用磷元素改性高岭土型流化床催化裂化(FCC)催化剂,热重-程序升温脱附(TG-TPD)和红外(IR)酸性测试结果表明,磷改性的催化剂,能够降低催化剂总酸量,弱酸量和强酸量,可增加中强酸的酸量,可以降低催化剂的B酸强度和L酸中心数。在微反活性和小型固定流化床装置上评价了磷改性催化剂的反应性能,经过磷改性的催化剂,可提高催化活性,增强重油转化能力,改善焦炭和汽油选择性。     

中大孔催化裂化催化剂研究进展

发展中大孔型催化剂是催化裂化催化剂的主要发展方向之一,催化裂化催化剂中引入中大孔的主要方法有高岭土酸碱改性法、引入大孔硅铝基材料法、引入介孔分子筛法、原位晶化法和模板法。酸碱改性高岭土的孔结构受原料影响较大,孔径一般小于10 nm;制备大孔硅铝基材料替代拟薄水铝石可有效改善催化剂的孔结构,但应关注对催化剂强度的影响;分子筛中引入介孔又包括水热处理法,酸、碱处理法和引入不稳定位点法,工业应用范围广,但处理过程中易造成Y型分子筛结晶度下降,并缺乏连续、贯通型孔道;原位晶化法是工业上较成功的中大孔催化剂制备方法,但能耗相对高,流程长;模板法可通过改变模板类型、含量对催化剂孔结构调变,但应关注环保及催化剂强度问题。     

硫酸改性偏高岭土催化剂对甲醇制二甲醚性能的影响

为了研究不同浓度硫酸改性偏高岭土催化剂对甲醇制二甲醚性能的影响,制备出一系列不同浓度硫酸改性偏高岭土催化剂,并对催化剂进行表征分析和活性测试.结果表明,偏高岭土经过硫酸改性后,随着酸浓度的增加,催化剂表面出现明显的B酸和L酸,且L酸中心数目是催化剂合成二甲醚的主要影响因素;随着硫酸浓度增加,酸改性偏高岭土催化剂中高岭石...     

改性高岭土性能的研究

采用N2吸附、IR酸性表征和SEM等手段研究碱改性或酸改性高岭土的孔体积、比表面积、酸性及形貌特征。采用改性后高岭土部分替代高岭土制备FCC催化剂,并利用ACE对制备的3种催化剂进行性能评价对比。结果表明,高岭土经过酸碱改性后,碱改性高岭土的孔体积为0.30 mL·g-1,比表面积为111 m2·g-1;酸改性高岭土的孔体积为0.27 mL·g-1,比表面积为146 m2·g-1,孔体积和比表面积均有大幅提高,表现出一定的L酸酸性。改性后高岭土部分替代高岭土制备的FCC催化剂抗重金属污染能力较强,重油转化能力提高,碱改性高岭土制备的催化剂活性更高,但焦炭产率较高。     

催化裂化催化剂的酸性调变方法

综述了不同改性方法对催化裂化(FCC)催化剂的酸性调变作用以及对催化裂化反应性能的影响,主要包括脱铝改性、稀土改性、磷改性和镁改性等,对催化裂化催化剂的设计具有重要意义。     

Evaluation of surfactant-aided degumming of vegetable oils by membrane technology

The first step in the process of vegetable oil refining is degumming, in which phospholipids and mucilaginous gums are removed that otherwise result in a low-grade oil. A membrane process is remarkably simple yet potentially offers many advantages in degumming. Studies were conducted on surfactant-aided membrane degumming with soybean and rapeseed oils in a magnetically stirred flat membrane batch cell with different types of microfiltration membranes. The reduction of phospholipids in soybean oil was in the range of 85.8–92.8% during the membrane process. The phosphorus content of membrane permeates of soybean oil was in the range of 20–58 mg/kg. Crude rapeseed oil contained higher amount of nonhydratable phospholipids and hence resulted in lower reduction in phospholipids, in the range of 66.4–83.2%. Addition of hydratable phospholipids could improve the efficiency of degumming in the membrane process without using any electrolyte, resulting in improvement of quality as well as quantity of the phospholipids.     

Physiological effects of alarm chemosignal emitted during the forced swim test

Two experiments were conducted. In the first, male rats were immersed for 25 min in fresh water or water previously swum in by another rat. Control rats were not immersed in water. Rats tested in water previously swum in by another rat were significantly less immobile than rats tested in fresh water. Water immersion resulted in significant increases in serum corticosterone, glucose, and phosphorus levels, a decrease in potassium levels, and a higher phosphorus/potassium ratio, compared to nonimmersed controls regardless of water condition. When the two water-immersed groups were compared, rats tested in previously swum water had significantly higher glucose and significantly lower potassium levels and a higher phosphorus/potassium ratio than rats tested in fresh water. Immobility times were significantly correlated with the phosphorus/potassium ratio. In the second experiment, blood gases were measured prior to testing and at 25 min after immersion in rats tested in fresh and previously swum water. Rats in soiled water hypoventilated to a significantly greater extent than rats in fresh water but did not differ significantly in blood oxygenation. These two studies demonstrate that alarm chemosignals can produce physiological effects in conspecifics.     

Effects of decomposing rice straw on growth of and nitrogen fixation byRhizobium

Five phenolic compounds produced by decomposing rice straw and sterile extracts of decomposing rice straw in soil were very inhibitory to growth of three strains ofRhizobium. The effects were additive and in several instances synergistic. The phenolic compounds also reduced nodule numbers and hemoglobin content of the nodules in two bean (Phaseolus vulgaris) varieties. Extracts of decomposing rice straw in soil (same concentration as in the soil) significantly reduced N₂ fixation (acetylene reduction) in Bush Black Seeded beans. This may explain in part the great reduction in soybean yields in Taiwan following rice crops when the rice stubble is left in the field.     

Streptozotocin-Induced Diabetes Causes Changes in Serotonin-Positive Neurons in the Small Intestine in Pig Model

Serotonin (5-hydroxytryptamine or 5-HT) is an important neurotransmitter of the central and peripheral nervous systems, predominantly secreted in the gastrointestinal tract, especially in the gut. 5-HT is a crucial enteric signaling molecule and is well known for playing a key role in sensory-motor and secretory functions in the gut. Gastroenteropathy is one of the most clinical problems in diabetic patients with frequent episodes of hyperglycemia. Changes in 5-HT expression may mediate gastrointestinal tract disturbances seen in diabetes, such as nausea and diarrhea. Based on the double immunohistochemical staining, this study determined the variability in the population of 5-HT-positive neurons in the porcine small intestinal enteric neurons in the course of streptozotocin-induced diabetes. The results show changes in the number of 5-HT-positive neurons in the examined intestinal sections. The greatest changes were observed in the jejunum, particularly within the myenteric plexus. In the ileum, both de novo 5-HT synthesis in the inner submucosal plexus neurons and an increase in the number of neurons in the outer submucosal plexus were noted. The changes observed in the duodenum were also increasing in nature. The results of the current study confirm the previous observations concerning the involvement of 5-HT in inflammatory processes, and an increase in the number of 5-HT -positive neurons may also be a result of increased concentration of the 5-HT in the gastrointestinal tract wall and affects the motor and secretory processes, which are particularly intense in the small intestines.     

污泥生物炭中氮硫行为及环境效应研究进展

污泥生物炭中氮硫元素含量高,其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中,研究者往往以富碳生物炭作为主要研究对象,关注碳对全球气候变化的行为和功效,而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程,再到生物炭的老化,逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述,并对未来应注重开展的研究方向进行展望,为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明,污泥中氮元素含量普遍高于硫元素,且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加,在三相产物中的分配都是炭中持续减少,油中先增后减,气中一直增加。高温（＞800℃）条件下,气相中的氮含量高于固相,而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明,污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。     

咪鲜胺在粤浙两地水稻和土壤中残留动态

为了评价咪鲜胺在水稻上使用后的残留动态及环境安全性，在广东、浙江两地同时进行了咪鲜胺在水稻上的残留动态试验。结果表明：在广东地区，咪鲜胺在植株中的半衰期为2．59d，在土壤中的半衰期为2．46d，在稻田水的半衰期为0．46d；在浙江地区，咪鲜胺在植株中的半衰期为3．08d，在土壤中的半衰期为1．89d，在稻田水的半衰期为1．52d。收获的水稻糙米中咪鲜胺最终残留量均低于0．5mg／kg。     

分别测定双磷酸酯阻燃增塑剂中氯和溴含量的方法

介绍利用Ｂｒ的特征反应使系统中的Ｂｒ全部转化后，分别测定阻燃增塑剂中氯与溴含量的一种新方法。该方法分析速度快，操作简单，测定结果准确，重现性好，可应用于生产中的控制分析。     

Incubating superphosphate in ‘dry’soil can reduce its effectiveness

Single superphosphate was incubated for six months at 25°C in soil which had been subject to one of three moisture treatments. These were: dried in a glasshouse, dried at a constant temperature of 25°C, or moist soil. Phosphorus (P) effectiveness was then compared with effectiveness of P from freshly-applied superphosphate using yields of wheat (Triticum aestivum) and triticale (×Triticosecale) tops in pot experiments.Incubation in soil which had been dried at 25°C did not decrease the effectiveness of the P. Incubation in moist soil decreased it to about 20% of the effectiveness of freshly-applied P in one case and to about 50% in the other case. Incubation in soil which had been dried in a glasshouse also decreased its effectiveness. The decrease varied with conditions, but in two cases the P was 70% as effective as freshly-applied P, and in one case only 45% as effective. Presumably sufficient moisture was present in the soil dried in the glasshouse to enable water-soluble P present in the fertilizer to react with the soil.     

H-Ferritin Produced by Myeloid Cells Is Released to the Circulation and Plays a Major Role in Liver Iron Distribution during Infection

During infections, the host redistributes iron in order to starve pathogens from this nutrient. Several proteins are involved in iron absorption, transport, and storage. Ferritin is the most important iron storage protein. It is composed of variable proportions of two peptides, the L- and H-ferritins (FTL and FTH). We previously showed that macrophages increase their expression of FTH1 when they are infected in vitro with Mycobacterium avium, without a significant increase in FTL. In this work, we investigated the role of macrophage FTH1 in M. avium infection in vivo. We found that mice deficient in FTH1 in myeloid cells are more resistant to M. avium infection, presenting lower bacterial loads and lower levels of proinflammatory cytokines than wild-type littermates, due to the lower levels of available iron in the tissues. Importantly, we also found that FTH1 produced by myeloid cells in response to infection may be found in circulation and that it plays a key role in iron redistribution. Specifically, in the absence of FTH1 in myeloid cells, increased expression of ferroportin is observed in liver granulomas and increased iron accumulation occurs in hepatocytes. These results highlight the importance of FTH1 expression in myeloid cells for iron redistribution during infection.     

Lymphatic Transport of α-Linolenic Acid and Its Conversion to Long Chain n-3 Fatty Acids in Rats Fed Microemulsions of Linseed Oil

In the present study we evaluated the uptake of ALA and its conversion to EPA + DHA in rats given linseed oil (LSO) in native form or as a microemulsion in whey protein or in lipoid. In a single oral dose study in which rats maintained on rodent pellets deficient in ω-3 fatty acids were intubated with 0.35 g LSO in lipoid, the amount of ALA present in lymph was increased reaching a maximum concentration of 16.23 mg/ml at 2.5 h. The amount of ALA present in lymph was increased to a maximum level of 10.95 mg/ml at 4 h in rats given LSO as a microemulsion in whey protein. When LSO was given without emulsification, the amount of ALA present in lymph was found to reach a maximum level of 7.08 mg/ml at 6 h. A similar result was observed when weaning rats were intubated with 0.15 g of LSO per day for a period of 60 days. Higher levels of ALA by 41 and 103 % were observed in lymph lipids of rats given microemulsions of LSO in whey protein and in lipoid respectively as compared to rats given LSO without pre-emulsification. Very little conversion of ALA to EPA and DHA was observed in lymph lipids but higher amounts of EPA + DHA was observed in liver and serum of rats given LSO in microemulsion form. This study indicated that ALA concentration in lymph lipids was increased when LSO was given in microemulsion form in lipoid and further conversion to EPA and DHA was facilitated in liver and serum.